Archive for the ‘Work File Only – Observer’s Challenge Reports’ category

NGC 6857: Emission Nebula – Cygnus: October Observer’s Challenge Report #153

October 13, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

October 2021

Report #153

This is our “work-file report” for the Observer’s Challenge, used for organization, review and edits only. When all report submissions are received, personal photos are added and a final .pdf report will be issued by the 10th of the following month. (The cutoff date to receive submissions for the October report is November 8th).

Introduction

The purpose of the Observer’s Challenge is to encourage the pursuit of visual observing. It’s open to everyone who’s interested, and if you’re able to contribute notes and/or drawings, we’ll be happy to include them in our monthly summary. Visual astronomy depends on what’s seen through the eyepiece. Not only does it satisfy an innate curiosity, but it allows the visual observer to discover the beauty and the wonderment of the night sky. Before photography, all observations depended on what astronomers saw in the eyepiece, and how they recorded their observations. This was done through notes and drawings, and that’s the tradition we’re stressing in the Observer’s Challenge. And for folks with an interest in astrophotography, your digital images and notes are just as welcome. The hope is that you’ll read through these reports and become inspired to take more time at the eyepiece, study each object, and look for those subtle details that you might never have noticed before.

This month’s target:

William Herschel discovered NGC 6857 on 6 September 1784. His handwritten journal for that date reads: A patch containing some nebulosity…irregularly long.

Heinrich d’Arrest writes of this object and his observation of it in his 1867 Siderum Nebulosorum Observationes Havnienses. My very loosely paraphrased English for the Latin text: Minute, faint; it is most probably a cluster. A 12th-magnitude star precedes it. – Rechecked shortly after: it was not so small; not all of the nebula is resolved, there is at least some cloudiness. I’m not surprised that this was missed by Rosse.

NGC 6857 is the brightest part of the larger, star-forming emission region Sharpless 2-100, which is a much more difficult visual target than NGC 6857. 

A 2010 paper by Manash Samal and colleagues in the Astrophysical Journal indicates that the main ionizing source at the center of NGC 6857 is the bright, massive star at its heart. This compact nebula is estimated to be approximately 28 thousand light-years away from us, and the star is thought to have a spectral type of about O4III. The most likely age of the nebula is in the vicinity of 1 to 2 million years. (Intro and object information by Sue French)

Mario Motta: Observer from Massachusetts

An Interesting object, initially thought to be a planetary nebula, but upon careful inspection, clearly is not. NGC 6857 is the bright “knot” to the left (East) in the following image. The nebula is 40 arc sec in size, but is embedded in Sh 2-100, a faint H-Alpha emitting region. It’s really just a bright, but very small section of that nebula. The image was taken with my 32-inch telescope, 3 hours, 1 hour each Ha, S2, O3 filters, processed pixinsight, touched up in photoshop.

Venu Venugopal: Observer from Massachusetts

The image was taken using a 8-inch Newtonian, H-alpha, H-Beta, OII filter with a Zwo533MC 20 minutes exposure, 30 second sub frames at the ATMOB clubhouse in Westford, MA on 10/7/21.

NGC 6857 is an H III Ionized region in the Cygnus constellation.  It is a small (~1’) compact nebula. 3 stars in a row NE-SW, SW one brighter, the other two equal. The middle star is surrounded by nebulosity. The “hidden treasure” in the centre of Cygnus was found in 1784 when William Herschel discovers a “faint glow, among Milky Way stars”. It shows a triangle shape with darker center and hard defined V shaped straight edges.

Glenn Chaple: Observer from Massachusetts

NGC 6857 – Emission Nebula in Cygnus (Magnitude 11.4, Size 40”)

Astronomical literature notes that this month’s Observer’s Challenge, NGC 6857, is a planetary nebula that wasn’t. It was correctly identified as a faint nebula by William Herschel, who discovered it on September 5, 1784. Because of its small size and the presence of a false central star, it was later misclassified as a planetary nebula. Only in recent decades has NGC 6857 returned to its rightful status as a nebula – an emission nebula, to be exact.

NGC 6857 is located in the heart of Cygnus at 20h 01m 48s right ascension and +33° 31’ 38’ declination. It’s just 2 degrees SSE of the 4th magnitude star eta (η) Cygni, which was my starting point for a star-hop (see accompanying finder charts).

I observed NGC 6857 with a 10-inch f/5 reflector on an evening when the magnitude limit was around 5.0. I was unable to see it without the aid of OIII and narrowband filters. Even at 139x, it was small – appearing as a pale ghostly ‘flame’ emanating eastward from the vicinity of a 13th magnitude star.

NGC 6857 is part of a much larger but fainter emission nebula Sharpless 2-100. Approximately 30,000 light years away, its 40 arc-second apparent size translates to a true diameter of 9 light years.

Roger Ivester: Observer from North Carolina

NGC 6857 – Emission Nebula – Cygnus 

Date:  September 27th 2021 

Telescope:  10-inch f/4.5 Newtonian Reflector 

Sketch Magnification:  291x

Eyepiece Combination:  11mm + 2.8x Barlow 

NELM:  ~ 4.9 

After two nights of failure to see the emission nebula, NGC 6857 I gave up, but thought I’d give it one more try on the following night.  So, on the third night after two hours of careful observing using mostly averted vision and a high magnification of 291x, the nebula made its intermittent appearance.  

The nebula could best be described as very small and having an arc shape on the NE side of a faint star. 

Pencil sketch as following:  

Mark Helton: Observer from Massachusetts

Had a short stretch of clear skies last evening, so I thought that I would go for this months observers challenge.  This is NGC 6857. A small planetary nebula in the middle of a much larger region of hydrogen red nebula in the constellation of Cygnus.  It is very bright and also very small for my 535mm Stellarvue 102T-R scope.  It becomes that MM with my .08 Reducer/Flattener.  I shot this with my ZWO533MC Pro camera which has a one inch by one inch sensor.  Using a OPT Tirade Filter.  I only had about an hour and a half before the clouds rolled in, so this is 40, 180 sec images at medium gain.  Stacked in Nebulosity, and processed by Dave Rust, a new member of our club and friend of mine out in Bloomington, Indiana.  He has been introducing me to some new processing techniques so, I wanted him to give this target a try.  We are both using Photoshop, and Topaz Labs DeNoise for final processing.  Thinking of trying out Pixinsight, even though it is a bit of a learning curve.  I think to go to the next level of astrophotography, we have to make the jump!  Cygnus is just chock full of wonderful nebulae, it was fun to find this one.

NGC 6823/Sh 2-86: Open Cluster/Emission Nebula in Vulpecula: September Observer’s Challenge Report #152

September 13, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

September 2021

Report #152

NGC 6823 & Sh 2-86, Open Cluster & Emission Nebula in Vulpecula

Sharing Observations and Bringing Amateur Astronomers Together

Observer’s Challenge Report: Final

September 2021 OBSERVERS CHALLENGE _NGC 6823 & Sh 2-86

This month’s target:

The nebula surrounding the open cluster NGC 6823 suffers an identity crisis. It’s not NGC 6820, as many sources claim, but rather a small knot of nebulosity 16 arcminutes in position angle 218 degrees (southwest by south) from the bright quadruple star at the cluster’s heart. 

Here is NGC/IC maven Harold Corwin’s explanation:

NGC 6820 is a small knot of nebulosity, roughly 1′ × 1′, perhaps a reflection nebula around a few young stars or pre-stellar objects. It is specifically NOT the much larger HII region Sharpless 2-86 as has been many times been claimed, nor is it the cluster Collinder 404 = OCl 122, though that may 

represent the stars involved with the nebula. Marth’s original observation with Lassell’s 48-inch reflector mentions only the nebulosity: “F, S, R, bM”. [Faint, small, round, brighter in the middle]

http://haroldcorwin.net/ngcic/ngcnotes.all 

The position of NGC 6820 is 19h 42m 27.9s  +23° 05′ 15″. Consider this a bonus object if you’d like.

Information above compiled by Sue French

Sparse cluster with ~ 20 stars counted @ 160x, with a central concentration of several brighter members.  With careful and patient observing, despite the less than optimum transparency, and moving the cluster in-and-out of the view, from east to west, I could see some faint, but very large nebulosity ENE of the cluster.  No filter was used.  

To be able see the faint nebula after more than an hour was well worth the time, but once seen, it was surprisingly easy. RI

Pencil sketch as following, using a 10-inch reflector: Roger Ivester

Jaakko Saloranta: Observer from Finland (Pencil Sketch)

Sue French: Observer from New York (Pencil Sketch) 10-inch Reflector

M57, Planetary Nebula in Lyra: August 2021 Observer’s Challenge Report #151

August 17, 2021

august-2021-observers-challenge-_m57Download


Roger Ivester: Observer from North Carolina

10-inch reflector, fairly bright with well defined edges, gray in color, oval shape with a center void.  Both the NW and SW sides are brighter with greater concentration.  The ring is much lighter, or thiner on the NW, and also on the SE, but more subtle.  A 12th magnitude star lies, so very close to the east of the ring.

3.5-inch Maksutov-Cassegrain telescope at a magnification of 146x, the ring nebula is presented as very dim, round but mostly featureless. The central void can be seen, but fairly difficult.  

102mm refractor at 175x, shows the ring as surprisingly bright on this night of exceptional viewing with sharp and well defined edges.  The center void can be seen, but only as a lighter round gray spot, within the ring. Bright star just to the east.

Pencil sketch below:  

NGC 5746, Galaxy in Virgo: June 2021 Observer’s Galaxy Report #149

June 14, 2021

Monthly Observer’s Challenge

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

June 2021

NGC 5746, Galaxy in Virgo

Sharing Observations and Bringing Amateur Astronomer’s Together

MONTHLY OBSERVER’S CHALLENGE

june-2021-observers-challenge-_ngc-5746Download

This month’s target

William Herschel discovered NGC 5746 on 24 February 1786 with his 18.7-inch reflector. His handwritten journal reads:” Extremely bright, much extended in the parallel, 8 or 9 arcminutes long, bright nucleus.”

A recent study by John Kormendy and Ralf Bender in the Astrophysical Journal presents NGC 5746 as a structural analog of our own galaxy. Both are “are giant, SBb–SBbc galaxies with two pseudobulges, i.e., a compact, disky, star-forming pseudobulge embedded in a vertically thick, ‘red and dead,’ boxy pseudobulge that really is a bar seen almost end-on.” According to the authors, the lives of these galaxies have been dominated by minor mergers and bar-driven evolution for most of the history of the universe. They place NGC 5746 at a distance of 26.7 Mpc (87 million light-years). https://ui.adsabs.harvard.edu/#abs/2019ApJ…872..106K/abstract

NGC 5746’s V(V_T) visual magnitude is 10.32 ± 0.13, and its surface brightness is 12.6. The galaxy’s visible extent through medium-size amateur telescopes under dark skies is in the vicinity of 7.4′ × 1.3′.

Roger Ivester: Observer from North Carolina

NGC 5746 – Galaxy in Virgo 

Date:  May 30, 2021

Telescope:  6-inch f/6 Newtonian 

Sketch Eyepieces:  16mm + 1.9x Barlow 

Magnification:  109x

Field of View:  0.60º

Very easy to locate and see using 46x, mostly in-part being only 20 arc minutes West of bright star,  3.7 magnitude 109 Virginis.  

My best view came at 109x, and presenting the galaxy as highly elongated, oriented almost perfectly N-S.  The core is fairly bright and elongated with faint extensions, coming to a point at both the N and S tips.  

For my sketch, I moved 109 Virginis out of the field of view, to reduce the extreme glare.  

Globular Cluster, M3, NGC 5272 in Canes Venatici: May 2021 Observer’s Challenge Report #148

May 19, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

May 2021

Report #148

Messier 3 (NGC 5272), Globular Cluster in Canes Venatici

Sharing Observations and Bringing Amateur Astronomers Together

Introductio

This month’s target

Charles Messier discovered M3 on 3 May 1764 with a 3.5-inch refractor. The French text of Messier’s catalog in the Connaissance des Temps translates into English as: “Nebula discovered between the Herdsman and one of the Hunting Dogs of Hevelius; it does not contain a star, the center is brilliant & its light imperceptibly fades, it is round; when the sky is good, one can see it with a refractor of one foot [at the time, telescopes were generally described by their length]; it is reported on the Chart of the Comet observed in 1779. Mémoires de l’Académie of the same year. Reexamined 29 March 1781, still very beautiful.”

According to William H. Harris’ Catalog Of Parameters For Milky Way Globular Clusters,

http://physwww.mcmaster.ca/~harris/mwgc.dat , M3 resides 10.2 kiloparsecs (~33,000 light-years) away from us and 12.0 kiloparsecs (~39,000 light-years) from the galactic center. It shines with an integrated V-magnitude of 6.19, and the spectral type of the integrated cluster light is F6. Does its color look slightly yellow to you?

May 2021 Observer’s Challenge Complete Report: may-2021-observers-challenge-_m3-2

Roger Ivester: Observer from North Carolina

M3 (NGC 5272) globular cluster in Canes Venatici 

Date: March 2021 

Telescope:  10-inch f/4.5 reflector

Eyepiece:  20mm + 2.8x Barlow 

Sketch magnification 160x

Field of View:  0.38º 

80mm refractor:  Little or no resolution, appearing mostly round with an intense core, and a fainter enveloping halo.  

10-inch reflector at 160x:  Excellent resolve of stars, mostly round, and with a large number of outlier stars beyond the halo.  A very interesting dark lane was noted in the SE-NE of the cluster.  

NGC 3226 and NGC 3227, Galaxies in Leo: April 2021 Observer’s Challenge Report #147

April 16, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

April 2021

Report #147

NGC 3226 & NGC 3227, Galaxies in Leo

Sharing Observations and Bringing Amateur Astronomers Together

This month’s target

William Herschel discovered this interacting galaxy pair on 15 February 1784 with his 18.7-inch speculum-metal reflector. His hand-written journal of the discovery reads: “Two nebulae almost close together. Perhaps 1½ or 2′ asunder, they are pretty considerable in size, and of a roundish form; but not cometic; they are very faint.” He also notes that on this night he first used: “A new, large object Speculum. It is very bright but not quite as distinct as my first, I shall however use it all the night.”

Together known as Arp 94, NGC 3226 and NGC 3227 are wedded in a gravitational dance 47.2 ± 0.2 million light-years away from us. Their complex dance has spawned a remarkable array of tidal tails as well as one tidal dwarf galaxy — a gravitationally bound condensation of gas and stars formed during the repeated encounters of the two parent galaxies.

The most recent journal paper on this captivating system can be perused here: https://www.aanda.org/articles/aa/full_html/2021/01/aa38955-20/aa38955-20.html

Observer’s Challenge Complete Report:

April 2021 OBSERVERS CHALLENGE _NGC 3226_NGC 3227

NGC 3226-3227: Interacting galaxy pair in Leo 

Date: March 2021

Telescope: 10-inch f/4.5 reflector 

Sketch Magnification: 114x

Field of View: 0.52º 

NGC 3227: Fairly bright, and easy to locate and see even at low magnification.  At 114x, elongated, oriented NW-SE, brighter central region, but subtle.  I first observed this galaxy pair and made my first sketch on April 14th 1993.   

NGC 3226: Much smaller and a fainter than NGC 3227, mostly round, but with a very slight elongation, NNE-WSW.  At 190x, and with averted vision, a stellar nucleus is visible.  Roger Ivester

Sue French: Observer from New York

Through my 130-mm refractor at 23×, I see a moderately faint glow at the position of the interacting pair NGC 3226 and NGC 3227. At 63× it becomes evident that two galaxies dwell here. Although their halos blend together, each harbors a small, distinct, brighter center. NGC 3227 is the brighter and larger galaxy of the pair, its oval façade leans east-southeast. Precariously perched on NGC 3227’s north-northeastern tip, NGC 3226 is wrapped in a halo that tips northeast.

NGC 3222 makes an appearance in the field of view 117×, 13′ west of the interacting duo. This little galaxy appears very dim and holds a weakly glowing, starlike nucleus. A 14th-magnitude star winks in and out of view near the galaxy’s SW×W edge. At this magnification, NGC 3226 grows brighter toward the center, while NGC 3227 displays an oval core with a prominent stellar nucleus. I estimate combined length of the pair to be about 41⁄2′.S

NGC 2685 – Galaxy In Ursa Major – March 2021- Observer’s Challenge Report # 146

March 18, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

March 2021

Report #146

NGC 2685, Galaxy In Ursa Major

Sharing Observations and Bringing Amateur Astronomers Together

march-2021-observers-challenge-_ngc-2685-2

Introduction

This month’s target

German astronomer Wilhelm Tempel discovered NGC 2685 in 1882 with an 11-inch refractor. Loosely translated, his discovery description reads: Good II-III; round; with a small star in the middle; stands 4′ south of a 10th-magnitude star. 

In the Hubble Atlas of the Galaxies, Allan Sandage states, “NGC 2685 is perhaps the most unusual galaxy in the Shapley-Ames catalogue.” While most astronomers would agree with this, there remain various opinions as to why. NGC 2685 is generally regarded as a polar ring galaxy wrapped in exterior hoops of gas and dust aligned nearly perpendicular to the plane of the galaxy’s lenticular disk. The rings may have been birthed by a merger and/or accretion event. A less touted viewpoint is that this galaxy is strongly warped, and the semblance of rings is merely the result of projection effects.

This perplexing galaxy lies roughly 50 million light-years away from us. As seen photographically, the unusual array of gas, dust, and resultant stars entwining the Helix gives rise to its name. The galaxy may also house a supermassive black hole. Sue French

Date: February 3, 2021

Telescope: 10-inch reflector

Sketch Magnification: 114x

Field of View: 1/2º

Description: Small, fairly bright, elongated NE-SW, brighter bulged center with a stellar nucleus. I last observed this galaxy on March 11, 1996, from the same location and telescope with almost identical results.

From my 5.0 NELM suburban location, it is very easy to locate and see with the 10-inch, but with very little fine detail. The stellar nucleus required a magnification of 183x, and averted vision. It was my plan to observe this galaxy with my 6-inch reflector for a comparison. Hopefully, I can make this comparison next year. Roger Ivester

NGC 1893 Open Cluster + IC 410 Emission Nebula – February 2021 Observer’s Challenge Report – Auriga #145

February 5, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

February 2021

Report #145

IC 1893 and IC 410, Cluster and Emission Nebula in Auriga

Sharing Observations and Bringing Amateur Astronomers Together

Introduction

This month’s target

John Herschel discovered the open cluster IC 1893 in 1827 with the 18¼-inch reflector at Slough in Buckinghamshire, England. His handwritten journal reads: “Rich, coarse, scattered and straggling. It more than fills the field. The stars are 9…15 magnitude.”  The engulfing nebula, IC 410, wasn’t discovered until 1892, when Max Wolf found some new extended nebulae on photographic plates taken with a 6-inch Voigtländer portrait lens. My paraphrased translation of the pertinent section of his discovery says: The ribbon-rich nebula shown on the plates around the star cluster surrounds the star BD+33 1023 [HD 242908] should also be new. It largely encloses the whole group.

The nebula is roughly 11,000 to 12,000 light-years distant, and the adolescent cluster within it is at least 4-million years old.

Complete Report: February 2021 OBSERVERS CHALLENGE _NGC 1893 and IC 410

IC 348 – Open Star Cluster Plus Nebula – Perseus – January 2021 Observer’s Challenge Report #144

January 2, 2021

Compiled by:

Roger Ivester, North Carolina 

&

Sue French, New York

January 2021

Report #144

IC 348 – Cluster plus Nebula in Perseus

Sharing Observations and Bringing Amateur Astronomers Together

This month’s target

During his term as the first director of Dearborn Observatory, Truman Henry Safford discovered IC 348 on December 1, 1866, with the observatory’s 18.5-inch refractor. Safford published his observation in a table of objects found at Dearborn in the years 1866–1868. The table uses the alphabet-soup notation common to the era, which decrypted means: very large, very gradually brighter in the middle, pretty bright. Additionally, a note below that section of the table describes the object as “A loose cluster with nebula.” The combo appeared in the First Index Catalogue.

IC 348 has the dubious honor of bearing two IC designations. Edward Emerson Barnard independently discovered the nebula in 1893, and it was placed in the Second Index Calalogue as IC 1985, without anyone tumbling to the fact that it was already in the previous IC catalog. Unlike Safford, Barnard didn’t note the existence of the cluster within the nebula. 

IC 348 is thought to be roughly 1000 light-years away and a youthful 2–3 million years old. It holds about 500 stars, with brightest being hot, blue-white stars on the main sequence. The cluster’s visual magnitude is 7.3. By Sue French

january-2021-observers-challenge-_ic-348


M76 – Planetary Nebula in Perseus – December 2020 Observer’s Challenge Report: #143

November 29, 2020

Compiled by:

Roger Ivester, North Carolina 

&

Sue French, New York

December 2020

Report #143

M76, Planetary Nebula in Perseus

Sharing Observations and Bringing Amateur Astronomers Together